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Rao. Vessel Plus 2022;6:24 https://dx.doi.org/10.20517/2574-1209.2021.91 Page 11 of 23

Figure 14. Echo frames from parasternal 2D and Doppler study illustrating tricuspid regurgitant jet (TRJ) by color flow imaging in (A)
and by continuous wave Doppler in (B). The magnitude of TRJ is used for the calculation of systolic pressure in the pulmonary artery.
The recorded peak velocity of 3.74 m/s by modified Bernoulli equation is calculated to be 56 mmHg gradient (see insert in B). 5 mmHg
is presumed right atrial (RA) pressure and should be added to this value. Right ventricle (RV) is labeled. Reproduced from Ref. [19] .

However, the sonographer must ensure that there is no evidence for obstruction within the right ventricle
(RV) (infundibular PS) or obstruction at valvar, supravalvar, branch PA level by methodical Doppler
interrogation.

Ventricular septal defect
In patients with ventricular septal defect (VSD), again, the outflow tract of the RV is examined to exclude
PS and the LV systolic pressure is assumed to be similar to the arm cuff BP following exclusion of
obstruction in the outflow tract of the LV. Doppler flow velocity through the VSD is recorded in [Figures 15
and 16]. One can usually assume an unrestrictive VSD if the VSD Doppler velocity is < 2.0 m/s [Figure 15]:

PAP = RVP = LVP

LVP, left ventricular peak systolic pressure (equals to systolic BP); PAP, pulmonary artery systolic pressure;
and RVP, systolic pressure in the right ventricle.

We can generally assume there is a restrictive VSD if the VSD Doppler velocity is > 2.0 m/s [Figure 16]. The
PA systolic pressure may be assessed by:

PAP = RVP = LVP - 4V 2

LVP, peak systolic pressure in the left ventricle (systolic BP), PAP, systolic pressure in the pulmonary artery,
RVP, systolic pressure in the right ventricle, and V, velocity magnitude of the VSD flow.

Pulmonary insufficiency jet
In subjects with pulmonary insufficiency jet [Figure 17], the PA diastolic pressure is estimated by the
formula:

PA pressure in diastole = 4V + 5 mmHg
2

V, magnitude of pulmonary insufficiency jet velocity. 5 mmHg is presumed RV end-diastolic pressure.